Massive offshore wind farms’ unexpected benefit: Hurricane protection

Wind speed, storm surge slashed when there are 10,000 turbines in storms' path.

At the recent meeting of the American Association for the Advancement of Science, Stanford researcher Mark Jacobson spoke in a session on renewable energy. Jacobson was in the session because he has developed roadmaps to convert the entire US to renewable energy, primarily wind, solar, hydroelectric, and wave/tidal. His detailed analysis includes looking at costs and benefits, including the obvious benefits to human health from the reduced pollution. But he spent one of his slides showing off a very unexpected benefit: the end of destructive hurricanes.

We'll get back to his thoughts on energy in a full report, but today Stanford released a video describing the storm suppression. Wind power plays a very significant role in Jacobson's plan, and many states don't have extensive on-shore wind resources. As a result, going entirely renewable involves building offshore wind on a truly massive scale, with many individual states sporting tens of thousands of turbines on the continental shelf.

And that will unsurprisingly have an effect on how winds propagate. Jacobson modeled three different hurricanes—Isaac, Katrina, and Sandy—plowing into a massive field of wind turbines. The wind speeds dropped by up to 90 miles an hour, which is enough to drop all but the most powerful storms out of the hurricane category. In fact, the huge fields of turbines were so disruptive that the wind speed started to drop before it even reached the turbines, meaning that in many cases, they could safely continue generating energy throughout the storm.

Jacobson describes his modeling of hurricanes vs. wind farms.

In Sandy's case, the wind did very little direct damage; rather, the storm surge the winds drove was the primary culprit. But without the wind, the storm surge was underpowered. Depending on the precise details, it dropped by anywhere from six percent to nearly 80 percent.

In a paper that was also released today, Jacobson and some colleagues at the University of Delaware have calculated that all the benefits of the wind farms—improved health via lower pollution, reduced climate change, and hurricane mitigation—combine to make the net cost of electricity generated by these wind farms cheaper than if it were generated using fossil fuels. And despite the high cost of offshore wind, when those savings are considered in the total system costs, it becomes cheaper to build wind than it does to build seawalls to protect all vulnerable areas from storm surges.

Promoted Comments

Again, I doubt that it's capturing a significant enough amount of the energy of a hurricane. You do realize how huge hurricanes are, right? And how much energy they contain?

In the actual paper its explained that a large part of the effect on the hurricanes was not directly from stealing the energy but the first step in a longer chain to weaken the hurricane. Basically the turbines are knocking down the wind speeds some, which reduces wave height, which lowers surface friction, which reduces convergence in the eye region, which weakens the convection that drives the hurricane. The weaken convection results in a higher central pressure, and thus lowering wind speeds more. (If you can access the article, the longer for explanation is right after Figure 2)

All that said, I'm not sure I buy what the paper is selling. The premise is highly dependent on the surface effects of turbines and how well that is represented in the models. We were just talking about this paper here in the office and are highly dubious about how well the models handle turbines. (and "we" includes a couple of atmospheric modelers)